Virtual Reality Negotiation Training Increases Negotiation ...mmi.tudelft.nl/~joostb/files/Broekens...

of 13 /13
Virtual Reality Negotiation Training Increases Negotiation Knowledge and Skill Joost Broekens, Maaike Harbers, Willem-Paul Brinkman, Catholijn Jonker, Karel Van den Bosch, John-Jules Meyer Delft University of Technology [email protected], {m.harbers,w.p.brinkman,c.m.jonker}@tudelft.nl Utrecht University [email protected] TNO Human Factors Soesterberg [email protected] Abstract. In this paper we test the hypothesis that Virtual Reality (VR) negotiation training positively influences negotiation skill and knowl- edge. We discuss the design of the VR training. Then, we present the results of a between subject experiment (n=42) with three experimen- tal conditions (control, training once, repeated training) investigating learning effects on subjects’ negotiation skill and knowledge. In our case negotiation skill consists of negotiation outcome (final bid utility) and conversation skill (exploratory conversational choices in VR scenario), and negotiation knowledge is the subjects’ quality of reflection upon filmed behavior of two negotiating actors. Our results confirm the hy- pothesis. We found significant effects of training on conversation skill and negotiation knowledge. We found a marginally significant effect of training on negotation outcome. As the effect of training on negotiation outcome was marginally significant and only present when controlling for overshadowing effects of the act of reflecting, we postulate that other learning approaches (e.g., instruction) are needed for trainees to use the information gained during the joint exploration phase of a negotiation for the construction of a bid. Our results are particularly important given the sparse availability of experimental studies that show learning effects of VR negotiation training, and gives additional support to those studies that do report possitive effects such as with the BiLAT system. 1 Introduction Virtual Reality systems are effective tools to change human behavior in a wide variety of domains including training medical skils, education of children, mili- tary procedures, flying, but also the treatment of phobias through VR exposure therapy (see [22, 29, 19, 26, 28, 2]). A key characteristic of these systems is that they are effective at inducing cognitive and behavioral changes for a relatively constrained and well-defined setting. Systems that have shown to be effective include treating particular anxieties through exposure of the subject such as fear of heights [8], training particular skills such as teaching children to safely

Embed Size (px)

Transcript of Virtual Reality Negotiation Training Increases Negotiation ...mmi.tudelft.nl/~joostb/files/Broekens...

  • Virtual Reality Negotiation Training IncreasesNegotiation Knowledge and Skill

    Joost Broekens, Maaike Harbers, Willem-Paul Brinkman, Catholijn Jonker,Karel Van den Bosch, John-Jules Meyer

    Delft University of [email protected], {m.harbers,w.p.brinkman,c.m.jonker}@tudelft.nl

    Utrecht [email protected]

    TNO Human Factors [email protected]

    Abstract. In this paper we test the hypothesis that Virtual Reality(VR) negotiation training positively influences negotiation skill and knowl-edge. We discuss the design of the VR training. Then, we present theresults of a between subject experiment (n=42) with three experimen-tal conditions (control, training once, repeated training) investigatinglearning effects on subjects negotiation skill and knowledge. In our casenegotiation skill consists of negotiation outcome (final bid utility) andconversation skill (exploratory conversational choices in VR scenario),and negotiation knowledge is the subjects quality of reflection uponfilmed behavior of two negotiating actors. Our results confirm the hy-pothesis. We found significant effects of training on conversation skilland negotiation knowledge. We found a marginally significant effect oftraining on negotation outcome. As the effect of training on negotiationoutcome was marginally significant and only present when controllingfor overshadowing effects of the act of reflecting, we postulate that otherlearning approaches (e.g., instruction) are needed for trainees to use theinformation gained during the joint exploration phase of a negotiationfor the construction of a bid. Our results are particularly important giventhe sparse availability of experimental studies that show learning effectsof VR negotiation training, and gives additional support to those studiesthat do report possitive effects such as with the BiLAT system.

    1 Introduction

    Virtual Reality systems are effective tools to change human behavior in a widevariety of domains including training medical skils, education of children, mili-tary procedures, flying, but also the treatment of phobias through VR exposuretherapy (see [22, 29, 19, 26, 28, 2]). A key characteristic of these systems is thatthey are effective at inducing cognitive and behavioral changes for a relativelyconstrained and well-defined setting. Systems that have shown to be effectiveinclude treating particular anxieties through exposure of the subject such asfear of heights [8], training particular skills such as teaching children to safely

  • cross a street [32], a particular procedure such as emergency situtation triage[1], or a particular sensory-motor skill such as a specific type of surgery [12].More recently VR training has been proposed for ill-defined training tasks suchas cultural understanding, persuasion, social skills and negotiation, usually inthe form of a serious game [6, 25, 14, 30]. However, for these more complex, andoften ill-defined tasks, it is difficult to develop the right simulation content, sto-ryline, interactions, and outcome measures [14]. As a result of these difficultiesand the novelty of the field, there is only sparse evidence of such VR systemsshowing measureable learning effects, a point explicitly made in [30].

    We focus on negotiation support systems for novice negotiators and withinthat context aimed to develop a VR negotiation training. Only several accountsexist of experimentally verified learning effects of VR negotiation training [20,7], and with the same system (i.e., BiLAT, [18]). It is therefore important toinvestigate learning effects targeted at the same phenomenon (i.e., negotiationknowledge and skills) with a different system, because positive results couldeasily be tied to the specific choices of a system with respect to domain, imple-mentation, and content. In this paper we present an experiment with a virtualtraining system for negotiation that has been carefully constructed, involving avirtual agent that is able to express emotions and explain its behavior. VR nego-tiation training is in essence a role play between a human and a virtual human,as often used in traditional negotiation training. Therefore, the use of intelligentvirtual agents equipped with human-like capabilities such as emotion and expla-nation is a logical choice. This paper addresses two topics. First it describes indetail the design of the system, so that choices and assumptions are made ex-plicit. Second, we present results of an experiment investigating learning effectsof the training on negotiation skill and knowledge. In our case negotiation skillconsists of an outcome measure and a process measure; i.e., negotiation outcomeand conversation skill. We define negotiation outcome as the utility of the finalbid proposed by the subject. We define conversation skill as the number of timesa subject selects responses that open the conversation towards finding underly-ing concerns minus the number of times a subject selects responses directing theconversation towards a premature ending. In our scenario, opening responses areresponses that are polite, show interest in the other and ask for underlying in-terests instead of prematurely fix issues. We define negotiation knowledge as thesubjects quality of reflection upon the filmed behavior of two negotiating actors.Negotiation skill in our experiment thus measures in-game non-transferred skillsas displayed in the actual negotiation behavior of subjects while playing the VRscenario. Negotiation knowledge measures implicit knowledge transferred fromthe VR training to the analysis of negotiation behavior of others.

    In section 2 we provide background on negotiation and distill the require-ments for our negotiation training. In section 3 we discuss the design of VRnegotiation training in detail. In section 4 we present the experimental setupand results. Section 5 presents a more general discussion.

  • 2 VR Training requirements

    The naive view on a negotiation is that it is a single task aimed at claimingthe highest outcome value by bargaining the best price for a particular good.This naive view on negotiation has several important shortcomings resultingin a difficulty to reach a win-win outcome [10, 27, 31]. A win-win outcome isan agreed-upon bid that is optimal in terms of overall outcome value for bothsides of the negotiation. First, the naive view focusses on a single issue, i.e.,money, while any meaningful negotiation involves multiple issues, relationships,and emotions. Second, it focusses mainly on the bidding process and approachesbidding as bargaining (e.g., about price). This hinders getting a good overview ofall issues that play a role in the negotiation and thus limits the possibility to placeinteresting bids that are good for both sides. Third, and related to the previous, itdoes not emphasize the different phases in a negotiation process. Any negotiationcan be separated into at least four phases: preparation, joint exploration, biddingand closing (see, e.g., [15]). The preparation takes place before the negotiationpartners meet, and involves the collection of information about ones own andthe partners desires. In the exploration phase, the negotiation partners start toexplore each others wishes. Subsequently, in the bidding phase the negotiationpartners exchange actual bids, and in the closing phase the partners leave eachother with or without an agreement, make plans for further negotiation, re-negotiation, and make sure the relationship is well-managed.

    A more realistic view on negotiation is thus that it is a four step processinvolving the exploration of issue preferences of and by the different parties inthe negotiation in order to be able to get closure on a deal that has value for allparties and will be respected afterwards. Although such a process seems overkillfor simple day-to-day negotiations it is not [32]. Even the distribution of house-hold tasks among couples is a multi-issue negotiation including issues such asdoing the dishes, putting the kids to bed, cooking, and doing finances and taxes.Partners have preferences for or against doing these tasks and usually figure outa win-win bid that honors these preferences. These bids are renegotiable eachday, and often are being renegotiated. The bids are complete bids (I dont feellike doing the dishes, but I dont mind putting the kids to bed, etc.) and notbased on single issue bargaining. When getting home from work one usually haspreferences about the different tasks and in fact privately prepares the nego-tation. Then in a short exploration phase the different issues and preferencesare explored (I dont feel like doing X today, I dont mind Y, you dont mindX?, etc.). Several bids are exchanged, a deal is made and should be honored(no-one will get away in the long run with not honouring the fact that you saidyou would do the dishes but then simply decide not to). In fact these simplenegotiations are perfect examples of negotiations in separate phases, and showthe shortcomings of the naive view on negotiation: you rarely bargain about asingle household issue and then think it is fair to claim as much value (as littlework) as possible.

    The example also highlights the importance of ensuring a good relationship.Most negotiations involve a relation between the two negotiation partners. Even

  • after buying a car a relationship follows, albeit a very limited one (service agree-ment). This brings us to an important element in negotiation: emotion. Emotionsplay a role before, during and after a negotiation. People have preferences aboutissues that are in essence affective attitudes. People have an opinion about nego-tiation in general and about having to enter one in particular. People experienceemotions during negotiations, and use emotions strategically. As such, it is crit-ical to address and be aware of your own and the other sides emotions in anegotiation [9], and the importance of emotion in negotiation has been experi-mentally shown in a large number of psychological studies (for review [4]).

    An often-made mistake by novice negotiators in the joint exploration phaseis to only explore each others preferences on issues, e.g. the height of a salary,and forget to ask about the others interests, e.g. the need of enough money topay the mortgage. It is important to learn that by exploring someones interests,alternative solutions can be found that are profitable for both partners, e.g.a lower monthly salary but with a yearly bonus. This mistake was confirmedby a diary study we performed as a preparation for the development of thevirtual reality scenario. The study involved 8 subjects who were asked to keeptrack of their negotiation for a new job or a new house. Subjects often reportedabout issues, but rarely reported how these issues were derived from ones ownunderlying interests, let alone the interests of the other party.

    These case studies and theoretical analysis have been the basis for the re-quirements of our negotiation training. First, trainees must follow a phase-basednegotiation, with a clear separation between exploration and bidding. Second,emotions play an important role during the negotiation training. Third, thetraining should focus on investigating underlying concerns, rather than issues.

    3 VR Training design

    The main training goal is to make people realize the importance of, and getskilled at, investigating issues and interests (underlying concerns). The traininginvolves a negotiation about terms of employment and involves a human playerin the role of an employer and a virtual agent playing the future employee. Ithas two negotiation phases: the joint exploration phase and the bidding phase.The trainee can interact with the agent by selecting a conversational responsefrom a multiple choice selection (Figure 1). Choices influence the course of thescenario as explained below. The scenario is represented as a conversation treewith branches that can be conditionally activated or deactivated based on pre-vious choices. Total playtime averages around 10 minutes, and the tree consistsof about 150 sentence nodes. The virtual agent communicates in natural speech,pre-recorded by a professional voice actor. Beforehand, the virtual training andscenario were reviewed and approved by a professional negotiator.

    In more detail, the training scenario focuses on the exploration phase inwhich the trainee and the character explore each others standpoints concerningtopics such as monetary gain and commute time. A total of four topics are ex-plored in a fixed sequence. Throughout the scenario the trainee can make subtle

  • Fig. 1. The negotiation training showing two conversational options, the Virtual Char-acter and the explanation as a thought bubble (left). Emotional expressions (right).

    conversational choices approaching the topic either from an underlying interestpoint of view or an issue point of view. Conversational choices that approach thetopic based on underlying interests will eventually broaden the range of issuesthat can be used to resolve a conflict. The mechanism is the same for all fourtopics. Interest-based exploration will trigger the Virtual Character (VC) to in-troduce a non-distributive issue to resolve a conflict around a distributive issuefor a particular topic. Values for a distributive issue are positively related to theutility for one negotiator but negatively to the utility for the other (if one wins,the other looses), while values of a non-distributive issue have the same relationto the utility of both negotiators (both win or loose together). For example, ifthe trainee keeps asking about why the virtual character (the future employee)needs a particular salary, eventually the VC will tell the trainee that he is plan-ning a world trip in one year (interest) and needs to have a certain amount ofmoney for this, but that it is also possible to get this money as an end-of-yearpresentation-based bonus instead of a fixed salary. This should be acceptable tothe trainee as this limits the financial risk of hiring personnel and gives incentiveto the employee to work hard (the trainee is told in the role description thathe/she owns a startup and hence risk and motivated personnel is an importantthing to manage). The end-of-year bonus is a non-distributive issue that can beused to replace the distributive issue salary. All interests and issues used in thescenario are based on the diary studies.

    When all four topics in the exploration phases have been explored, the traineeconstructs one complete bid based on the issues that have been found dur-ing the exploration phase. This bid typically consists of distributive and non-distrubutive issues as found through conversation with the VC. For each topic

  • the trainee has three options, two are always available, the third has to be un-locked by exploring the agents interests in the exploration phase as explainedabove. The first option is the value for the distributive issue according to thetrainees original standpoint (hardliner). The second option is a compromisevalue for that issue, in between the trainees and VCs standpoint. The thirdoption is a win-win value for the non-distributive issue. The utility of the bidis scored as follows. For each non-distributive issue used in the bid the util-ity gain equals 2. For each compromise on a distributive issue the utility gainequals 1. For each hardliner value, the utility gain equals 0. This means thatthe utility ranges between 0 and 8 (4 topics in total). A win-win agreement isdefined as a utility>6, no agreement is defined as a utility

  • Figure 1) to offer explanations at the time they are most relevant, but withoutdisturbing the flow of the scenario.

    4 Experiment

    To evaluate training effects of the negotiation training, we have conducted anexperiment. Our main hypothesis was that VR negotiation training improves ne-gotiation knowledge and skills. We now detail the experimental design, protocol,subject sample and materials.

    4.1 Method

    We performed a standard between-subject experiment with three conditions. Inthe control condition subjects did not perform a VR training session prior tocollecting effect measures. In the single session condition subjects performed oneVR training session. In the repeated condition subjects performed 5 sessions. Aspreliminary studies with smaller number of subjects and only a single trainingsession did not show learning effects, the repeated condition was added to makesure subjects had enough training. One training session took approximately 10minutes. Table 2 shows the experimental protocol schematically.

    First, all subjects rated their daily life self-reported negotiation skill, nego-tiation liking, negotiation frequency, and negotiation perseverance when negoti-ating. Ratings were on a 5-point Likert scale. As Cronbachs alpha for the fouritems was acceptable (alpha=0.71), the four items were integrated into one con-struct measuring self-reported negotiation tendency. This tendency to negotiatethus consists of self-reported doing, liking, skill and perseverance in negotiation.

    Second, the subjects in the single session and repeated conditions performedthe VR negotiation training with explanations and emotions in an office settingbehind a standard desktop pc wearing headphones. Subjects in the single ses-sion condition were asked to play as well as possible. Subjects in the repeatedcondition were asked to explore the training in the first four sessions but toplay as well as possible in the 5th session. We recorded final negotation outcomeand conversation skill for both conditions. Subjects in the control condition didnothing but continued immediately with the next step in the protocol.

    Third, we presented each subject with 5 pre-recorded scenes showing a similarjob negotiation acted by two actors. Beforehand, the scenes had been judgedplausible by a professional negotiator. We asked subjects to take the role ofadvisor for the employer and write a reflection upon these scenes in an openresponse format. Subjects were asked to answer two questions per scene: Whatjust happened in the scene? And, what is your advice for the employer? Afterthe experiment two independent raters rated the quality of the reflection foreach subject based on the following coding scheme that identifies knowledge andunderstanding of negotiation:

    The advisor proposes to ask for the underlying reason for the employeespreference for part-time work (scene 1).

  • In case of an impasse, the advisor proposes to broaden the negotiation byexplicitly mentioning new issues or interests (scene 2, 3).

    The advisor proposes a clear closure of the negotiation (scene 4). The advisor assumes negotiation partners are equal: there are no signs of

    hierarchy, single-sided dependency, dominance or a battle for points. The advisor stresses the importance of a good atmosphere.

    For each item 1 point could be gained, effectively creating a 6 point scale (1-6).As the inter-rater reliability between the two raters was excellent (Cronbachsalpha=0.91) we combined the independent ratings, resulting in one rating persubject. This rating of reflection quality is our measure of negotiation knowledge.

    Finally, all subjects performed a test in which they played the VR negotiationscenario again. We recorded negotiation outcome and conversation skill. Subjectswere again asked to play as well as possible. 1

    Subjects (mean age=24.7, std=4.5) were recruited of two different univer-sities, and were gender balanced accross conditions, resulting in 7 males and 7females in each condition totalling 42 subjects, 14 in each condition. Assigmentto the conditions was random. The conditions did not differ significantly in age(ANOVA F(2, 39)=2.241, p=0.120), nor in self-reported negotiation tendency(ANOVA F(2, 39)=1.585, p=0.218).

    4.2 Main Results

    To investigate if VR training increases negotiation skill and knowledge, we per-formed a multivariate ANOVA with training condition as independent variableand test conversation skill, test negotiation outcome and negotiation knowl-edge as outcome measures.2. We found a significant effect of training (WilksLambda F(6, 74)=2.668, p=0.021). In detail we found a significant effect onnegotiation knowledge (F(2, 39)=4.315, p=0.020) and conversation skill (F(2,39)=3.668, p=0.035), but not on negotiation outcome (F(2, 39)=0.593, p=ns).Contrasts (LSD method) showed that lack of training results in a significantlylower rating for negotiation knowledge (mean=2.39, std=1.11) than a single ses-sion (mean=3.5, std=1.14, p=0.011) or repeated sessions (mean=3.39, std=1.04,p=0.021), and that lack of training results in a significantly lower (mean=-0.93, std=4.46) conversation skill than repeated training (mean=4.71, std=5.74,p=0.01). None of the contrasts between the three conditions were significant oreven approached significance for negotiation outcome (all p>0.32). Conversationskill after a single training did not significantly differ from either no training or

    1 Emotional facial expression and explanations were omitted, as we will use this test asbaseline performance in future experiments aimed at testing the influence of emotionand explanation as separate factors. A second reason to omit these is that they areinformative means of feedback aimed at learning, while we wanted to use this as atest.

    2 Gender effects were non-significant in a MANOVA with condition and gender as in-dependent variables (Wilkss Lambda F(6, 68)=2.438, p=0.081), and no interactioneffect between gender and training was found.

  • Fig. 2. Experimental conditions and protocol (top); dependent variables (our outcomemeasures; bottom).

    repeated training (mean=2.43, std=6.27, p=0.12 and p=0.28 respectively). Thisconfirms our hypothesis. Training has a positive influence on negotiation knowl-edge and conversation skill. Apparently more training is needed for gaining skill,but a single session of about 10 minutes is enough for gaining implicit knowledgeas measured by the quality of reflection on filmed scenes.

    As reflecting upon scenes could overshadow the effect of training on nego-tiation outcome, we performed a simple ANOVA with single versus repeatedtraining as independent variable and negotiation outcome taken from the singletraining session and the 5th repeated session before the reflections as outcomemeasure. The effect of single versus repeated training approached significance(F(1, 26)=4.002, p=0.056) with higher negotiation outcome for repeated train-ing (mean=4.21, std=1.31) compared to a single session (mean=3.29, std=1.13).To analyse the main effect of reflection, we performed a within-subject multivari-ate repeated measures ANOVA with reflection as independent variable and con-versation skill and negotiation outcome as dependents. We found a marginallysignificant effect of reflection (F(2, 26)=2.807, p=0.079), that was significantonly for conversation skill (F(1, 27)=5.480, p=0.027) with pre-reflection conver-sation skill being lower (mean=0.32, std=7.09) than post-reflection negotiatonskill (mean=3.57, std=6.02).

    4.3 Addional analyses

    In this section we highlight several trends and findings that are not directlyrelated to our main hypothesis, but are relevant for negotiation training.

  • Gender effects Gender effects approached significance for negotiation knowl-edge (F(1, 36)=3.55, p=0.068) and conversation skill (F(1, 36)=4.03, p=0.052).Female participants had lower negotiation knowledge ratings (mean=2.79, std=1.20)than males (mean=3.40, std=1.11) and they had lower post-reflection conver-sation skill ratings (mean=0.81, std=4.61) than males (mean=3.76, std=6.63).We found a significant effect of gender on self-reported negotiation tendency(F(1, 40)=11.380, p

  • skill and outcome. We interpret this as follows: good negotiators already un-derstand the link between exploration and bidding, while those that do not un-derstand this link can get knowledge and conversation skills out of VR trainingbut need additional forms of teaching (e.g., explicit instruction or negotiationrules) in order to understand the link. This lack of a learning effect is consis-tent with work described in the negotiation training literature [23] concludingthat pure experience-based learning is largely ineffective. Our results nuance thisconclusion slightly by supporting the following view: although experience-basedlearning does not positively influence the joint outcome, experience-based learn-ing does positively influence negotiation knowledge and conversation skills. Wehypothesize that the reason for the lack of a positive effect on the actual jointoutcome of the negotiation is due to participants inability to bridge the gapbetween exploring the negotiation space and translating the results of the explo-ration into a concrete bid. Future work should investigate if different negotiationphases need different learning approaches.

    We did not observe a clear effect of gender when it comes to negotiationoutcome, conversation skills and knowledge related to VR training and reflection.However, lower self-reported negotiation tendency for women does indicate thatfurther study towards gender differences in negotiation training should be done,especially since our results seem to indicate that this tendency to negotiate isrelated to negotiation skill in the VR training.

    Acknowledgments. This research is supported by the GATE project (NWOand ICT regie) as well as the Pocket Negotiator VICI-project 08075 (STW).Special thanks to Barnier Geerling from iamstudios for the voice acting, Markvan Gurp from Praction for evaluating the negotiation scenario and the filmedscenes, and Wietske Visser and Jeroen Meijer for rating reflection quality.

    References

    1. P. B. Andreatta, E. Maslowski, S. Petty, W. Shim, M. Marsh, T. Hall, S. Stern, andJ. Frankel. Virtual reality triage training provides a viable solution for disaster-preparedness. Academic Emergency Medicine, 17(8):870876, 2010.

    2. W. Brinkman, D. Hartanton, N. Kang, D. de Vliegher, I. Kampmann, N. Morina,P. M. G. Emmelkamp, and M. Neerincx. A Virtual Reality Dialogue System forthe Treatment of Social Phobia, page in press. 2012.

    3. J. Broekens, M. Harbers, K. Hindriks, K. v. d. Bosch, C. Jonker, and J.-J. Meyer.Do you get it? User-evaluated explainable BDI agents. In Proc. of MATES 2010,pages 2839. Springer-Verlag, 2010.

    4. J. Broekens, C. Jonker, and J.-J. Meyer. Affective negotiation support systems.Journal of Ambient Intelligence and Smart Environments, 2:121144, 2010.

    5. J. Broekens, C. Qu, and W.-P. Brinkman. Factors influencing user perception ofaffective facial expressions in virtual characters. submitted.

    6. M. Core, T. Traum, H. Lane, W. Swartout, J. Gratch, and M. Van Lent. Teachingnegotiation skills through practice and reflection with virtual humans. Simulation,82(11):685701, 2006.

  • 7. P. Durlach. Cultural awareness and negotiation skills training: Evaluation of aprototype semi-immersive system. Technical report, DTIC Document, 2008.

    8. P. Emmelkamp, M. Bruynzeel, L. Drost, and C. van der Mast. Virtual realitytreatment in acrophobia: a comparison with exposure in vivo. CyberPsychologyand Behavior, 4(3):335339, 2001.

    9. R. Fisher and D. Shapiro. Beyond reason: using emotions as you negotiate. Ran-dom House Business Books, 2005.

    10. W. U. Fisher, R. and B. Patton. Getting to yes: negotiating agreement withoutgiving in. Houghton Mifflin Harcourt,1991.

    11. D. Gomboc, S. Solomon, M. G. Core, H. C. Lane, and M. van Lent. Designrecommendations to support automated explanation and tutoring. In Proc. ofBRIMS 2005, Universal City, CA., 2005.

    12. T. P. Grantcharov, V. B. Kristiansen, J. Bendix, L. Bardram, J. Rosenberg, andP. Funch-Jensen. Randomized clinical trial of virtual reality simulation for laparo-scopic skills training. British Journal of Surgery, 91(2):146150, 2004.

    13. M. Harbers, J. Broekens, K. v. d. Bosch, and J.-J. Meyer. Guidelines for developingexplainable cognitive models. In Proceedings of ICCM10, pages 8590, 2010.

    14. M. Hays, A. Ogan, and H. Lane. The Evolution of Assessment: Learning aboutCulture from a Serious Game, pages 3744. 2010.

    15. K. Hindriks and C. Jonker. Creating human-machine synergy in negotiation sup-port systems: Towards the pocket negotiator. In W.-P. Brinkman, editor, Proc. ofthe 1st Int. Working Conference on Human Factors and Computational Models inNegotiation, HuCom 2008, pages 4754, Delft, 2008.

    16. L. Johnson. Agents that learn to explain themselves. In Proceedings of the Con-ference on AI, pages 12571263, 1994.

    17. F. Keil. Explanation and understanding. Annual Reviews Psychology, 57:227254,2006.

    18. J. M. Kim, J. R. W. Hill, P. J. Durlach, H. C. Lane, E. Forbell, M. Core, S. Marsella,D. Pynadath, and J. Hart. Bilat: A game-based environment for practicing nego-tiation in a cultural context. International Journal of Artificial Intelligence inEducation, 19(3):289308, 2009.

    19. M. Krijn, P. M. G. Emmelkamp, R. P. Olafsson, and R. Biemond. Virtual real-ity exposure therapy of anxiety disorders: A review. Clinical Psychology Review,24(3):259281, 2004.

    20. H. Lane, M. Hays, D. Auerbach, and M. Core. Investigating the Relationshipbetween Presence and Learning in a Serious Game Intelligent Tutoring Systems,volume 6094 of Lecture Notes in Computer Science, pages 274284. Springer Berlin/ Heidelberg, 2010.

    21. B. Malle. How people explain behavior: A new theoretical framework. Personalityand Social Psychology Review, 3(1):2348, 1999.

    22. F. Mantovani. Vr learning: Potential and challenges for the use of 3d environ-ments in education and training. In G. Riva and C. Galimberti, editors, Towardscyberpsychology: mind, cognition, and society in the Internet age, pages 207225,2001.

    23. J. Nadler, L. Thompson, and L. V. Boven. Learning negotiation skills: Four modelsof knowledge creation and transfer. Management Science, 49(4):529540, 2003.

    24. A. Ortony, G. L. Clore, and A. Collins. The Cognitive Structure of Emotions.Cambridge University Press, 1988.

    25. S. Parsons and P. Mitchell. The potential of virtual reality in social skills train-ing for people with autistic spectrum disorders. Journal of Intellectual DisabilityResearch, 46(5):430443, 2002.

  • 26. M. B. Powers and P. M. G. Emmelkamp. Virtual reality exposure therapy foranxiety disorders: A meta-analysis. Journal of Anxiety Disorders, 22(3):561569,2008.

    27. H. Raiffa. The Art and Science of Negotiation. Harvard University Press, 1982.28. M. Reznek, P. Harter, and T. Krummel. Virtual reality and simulation: Training

    the future emergency physician. Academic Emergency Medicine, 9(1):7887, 2002.29. A. Rizzo and G. Kim. A swot analysis of the field of virtual reality rehabilitation

    and therapy. Presence: Teleoperators and Virtual Environments, 14(2):119146,2005.

    30. E. v. d. Spek. Experiments in Serious Game Design. SIKS Dissertation series.University of Utrecht, Utrecht, 2011.

    31. L. L. Thompson. The Heart and Mind of the Negotiator. Pearson Prentice Hall,Upper Saddle River, N. J., 2005.

    32. J. Thomson, A. Tolmie, H. Foot, K. Whelan, P. Sarvary, and S. Morrison. Influenceof virtual reality training on the roadside crossing judgments of child pedestrians.Journal of Experimental Psychology: Applied, 11(3):175, 2005.

    33. M. Van Lent, W. Fisher, and M. Mancuso. An explainable artificial intelligencesystem for small-unit tactical behavior. In Proc. of IAAA 2004, Menlo Park, CA,2004. AAAI Press.